Abstract 157: DUSP6 modulates migration and glycolysis in PDAC cells
Authors: Mariana T. Ruckert, Bailey A. Bye, Michael N. VanSaun, Vanessa S. Silveira
Journal: Cancer Research (2022)

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive tumor and is the seventh cause of death for cancer worldwide, fifth in the US. The highly malignant profile is mainly caused by the constitutive activation of mutant KRAS - found in approximately 90% of PDAC cases. The undruggability of genetic KRAS mutations has led to efforts to find new therapeutical targets that focus on downstream molecules in this pathway. DUSP6 is a dual-specificity phosphatase that regulates ERK1/2 phosphorylation and, therefore, downstream RAS pathway activation. DUSP6 has been demonstrated to be differentially expressed during PDAC tumorigenesis, which we believe is critical for tumor progression and metastasis. In silico analysis on the TCGA dataset revealed that DUSP6 is overexpressed in primary tumor samples compared to normal pancreatic tissue. This data was confirmed in an independent dataset (GSE71729) that further revealed DUSP6 overexpression in metastatic samples compared to primary tumor samples. Additionally, patients with higher DUSP6 expression have worse overall survival than patients with low DUSP6 expression (P = 0.039), reaffirming its clinical relevance. We then assessed DUSP6 expression in tumor sections derived from KC and KPC mice using the RNAscope technology and observed that DUSP6 was strongly overexpressed in tumorigenic lesions, and largely co-localized with KRT19 expression. Using BCI - a pharmacological DUSP6 inhibitor - we observed significantly reduced viability in vitro in all the cell lines (P &amp;lt; 0.0001). DUSP6 inhibition also promoted ERK1/2 activation, as expected. Surprisingly, we observed that BCI-mediated DUSP6 inhibition increased migratory capacity in AsPC-1 (P &amp;lt; 0.0001), but not on BxPC-3 cells. Furthermore, murine AKC cells presented the completely opposite phenotype, with a significant decrease in migratory capacity (P &amp;lt; 0.0001), indicating a possible context dependent response. To further understand the molecular mechanisms behind DUSP6 in PDAC, we performed a gene set enrichment analysis using the TCGA and GSE15471 datasets and observed a strong correlation between DUSP6 and the glycolysis pathway. Therefore, we knocked down DUSP6 in K8484 cells and evaluated their proliferation in response to 2-DG, which was significantly decreased in comparison to treated parental cells (P &amp;lt; 0.001). In accordance with that, DUSP6 knockdown cells were significantly more impacted by 2-DG treatment than the parental cells regarding migratory capacity, bringing it to the basal level. Collectively, these results suggest that DUSP6 appears to modulate the metastatic process, and this phenotype correlates with the altered glycolytic capacity of pancreatic cancer cells. We are currently expanding our studies to additional cell lines and using in vivo models to further investigate if the observed phenotype is context dependent. To assess glycolytic changes in the cells, we are currently performing Seahorse-based assays. Citation Format: Mariana T. Ruckert, Bailey A. Bye, Michael N. VanSaun, Vanessa S. Silveira. DUSP6 modulates migration and glycolysis in PDAC cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 157.